Without alcohol injection or ported heads, you'll need to swap in some race gas to run safe low 12's in a TR. A turbo regal in "Race Trim" will always be faster than the same car in street trim.
I've driven my car one way for 3 hours (190 miles), put in race gas, changed chip, raised the boost, run five 11.6-11.7's without changing tires, put the street gas back in and drove home, with Zero problems. This is with a 90 thousand mile unmodified stock long block and minimal bolt on mods. Lots of other people have driven longer and run quicker.
Streetable is a relative term, but there are a few 9 second streetable TR's around here (ones that are actually driven on the street). Of course they are stage 2 cars.